/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.util.MultiMap');
/**
* @summary A simple multimap template.
* @template T
*/
shaka.util.MultiMap = class {
/** */
constructor() {
/** @private {!Map<string, !Array<T>>} */
this.map_ = new Map();
}
/**
* Add a key, value pair to the map.
* @param {string} key
* @param {T} value
*/
push(key, value) {
if (this.map_.has(key)) {
this.map_.get(key).push(value);
} else {
this.map_.set(key, [value]);
}
}
/**
* Get a list of values by key.
* @param {string} key
* @return {Array<T>} or null if no such key exists.
*/
get(key) {
if (!this.map_.has(key)) {
return null;
}
// slice() clones the list so that it and the map can each be modified
// without affecting the other.
return this.map_.get(key).slice();
}
/**
* Get a list of all values.
* @return {!Array<T>}
*/
getAll() {
const list = [];
for (const value of this.map_.values()) {
list.push(...value);
}
return list;
}
/**
* Remove a specific value, if it exists.
* @param {string} key
* @param {T} value
*/
remove(key, value) {
if (!this.map_.has(key)) {
return;
}
const newValue = this.map_.get(key).filter((i) => i != value);
this.map_.set(key, newValue);
if (!newValue.length) {
// Delete the array if it's empty, so that |get| will reliably return null
// "if no such key exists", instead of sometimes returning an empty array.
this.map_.delete(key);
}
}
/**
* Clear all keys and values from the multimap.
*/
clear() {
this.map_.clear();
}
/**
* @param {function(string, !Array<T>)} callback
*/
forEach(callback) {
this.map_.forEach((value, key) => {
callback(key, value);
});
}
/**
* Returns the number of elements in the multimap.
* @return {number}
*/
size() {
return this.map_.size;
}
/**
* Get a list of all the keys.
* @return {!Array<string>}
*/
keys() {
return Array.from(this.map_.keys());
}
};